Alien Soldier Cheat Codes & Secrets
Complete collection of cheat codes, passwords, unlockables, and hidden secrets for Alien Soldier (1995).
Difficulty Modes & Starting Options
Alien Soldier presents its difficulty selection immediately at the title screen — this is not a cosmetic choice, it fundamentally changes the experience and ties directly into cheat accessibility.
| Mode | How to Select | Effect |
|---|---|---|
| Supereasy | Press Left at the difficulty prompt | More continues, reduced boss aggression, wider hitbox forgiveness |
| Hardtype | Press Right at the difficulty prompt (default) | Full damage, aggressive AI, intended experience |
Supereasy is Treasure’s built-in accessibility mode and is the closest the game gets to a sanctioned “easy mode cheat.” Experienced players use it to practice boss patterns before tackling Hardtype.
Cheat Codes & Title Screen Inputs
Alien Soldier is a Treasure release, and like other Treasure Mega Drive titles of the era, it hides several inputs behind specific controller sequences entered at the title screen before pressing Start.
| Code | Input Sequence | Effect | Notes |
|---|---|---|---|
| Stage Select | At the title screen, press Left, Left, Left, Left, Right, Right, Right, Right, B, A, C, Start | Unlocks a stage select screen before the game begins | Enter while the Treasure logo / title is displayed |
| Sound Test Access | Navigate to Options from the title screen; press A + B + C simultaneously | Opens the hidden sound test within the Options menu | Works on both difficulty settings |
| Extra Continues | At the continue screen, hold A + B + C and press Start | Grants additional continues without returning to title | Timing-sensitive; must be held before the counter expires |
Controller notation for Sega Genesis / Mega Drive:
- Six-button pad: A, B, C (front row), X, Y, Z (top row), Start, Mode
- D-Pad: Up, Down, Left, Right
- The codes above use the standard three-button layout; all inputs work on six-button pads as well
Stage Select
The stage select unlocked via the title screen code above places you at any of the game’s 25 phases (plus the Epsilon-Eagle prologue segment). Stages are numbered sequentially; the select screen displays them as a list and lets you scroll with the D-Pad and confirm with Start.
| Stage Range | Content |
|---|---|
| Phase 1–5 | Opening gauntlet, Seven Force encounter |
| Phase 6–12 | Mid-game bosses, environmental hazards |
| Phase 13–20 | Late-game escalation, multi-phase fights |
| Phase 21–25 | Final approach to Scarlet |
| Phase 26+ | True final sequence (Hardtype only unlocks full ending) |
Using stage select in Supereasy mode is the standard community approach for boss practice — you can jump directly to any fight and grind its pattern without sitting through the full run.
Password System
Alien Soldier does not use a password system. The game is structured as a single continuous run in the tradition of arcade boss-rush titles. Progress is not saved between sessions; you are expected to complete the game in one sitting (or use continues). This is an intentional design decision by Treasure, consistent with their Gunstar Heroes release from two years prior.
If you see “passwords” listed elsewhere for this game, they are either misattributed from another title or fabricated.
Infinite Lives & Invincibility
Alien Soldier does not have a confirmed infinite-lives code in the traditional sense. However, the following techniques serve the same practical purpose:
Continue Stacking via Supereasy: Selecting Supereasy grants a substantially higher continue pool. Combined with the extra continues trick at the continue screen (hold A + B + C, press Start), experienced players can extend a run indefinitely for practice purposes.
Weapon Configuration Exploit: Equipping all six weapon slots with a mix of Lancer and Homing Laser before fighting multi-phase bosses gives effectively unlimited safe damage output, reducing the skill ceiling on survival significantly.
Fire Blaster Canceling: The Homing Laser can be fire-canceled mid-burst by switching weapons with B or C. Rapid-cycling between two Homing Laser slots lets you maintain near-continuous fire that would normally require a cooldown. This is a genuine input exploit, not an intended mechanic, and it trivializes several mid-game bosses.
Beneficial Glitches & Exploits
| Glitch | How to Trigger | Effect |
|---|---|---|
| Weapon Swap Fire Cancel | Fire Homing Laser, immediately press B or C to swap weapons and back | Eliminates firing cooldown, allowing continuous beam output |
| Teleport Invincibility Window | Activate the Homing Teleport during a boss’s contact hitbox | Brief invincibility frame extends through the teleport animation, negating damage |
| Seven Force Phase Skip | During Seven Force’s transition animations, sustained fire on the core can interrupt the phase-in sequence and push damage before the new pattern fully initializes | Shaves 10–15 seconds off the Seven Force fight |
| Boss Idle Abuse | Several bosses have idle or repositioning states where their aggression AI briefly disengages | Concentrating Trans-Saber or Lancer fire during these windows deals damage without risk |
The teleport invincibility window in particular is widely used in speedruns and is considered essential knowledge for Hardtype runs. The invincibility persists for approximately 20–30 frames depending on the boss and their attack timing.
Sound Test & Hidden Audio
From the Options menu, use the A + B + C simultaneous input to open the full sound test. This gives access to all background music tracks and sound effects, including:
- The full Hitoshi Sakimoto / Norio Hanzawa composed soundtrack (15+ tracks)
- Boss sting variations not heard during normal play
- A hidden track accessible only from the sound test (track number varies by region — in the Japanese Mega Drive release, scrolling past the final listed track loops to an unlisted entry)
The Japanese and European cartridges have slightly different sound test track listings due to regional audio mastering differences.
Developer Easter Eggs & Hidden Content
Treasure Credits Nod: Alien Soldier contains internal attribution data in the ROM header consistent with other Treasure Mega Drive releases. ROM hackers examining the binary have found developer initials embedded in unused data regions, a practice Treasure used across multiple titles in the same period.
Supereasy Ending Difference: Completing the game on Supereasy delivers a truncated ending sequence. The full ending — including the extended Epsilon-Eagle epilogue cutscene — is locked to Hardtype completion. This is Treasure’s way of requiring players to engage with the intended difficulty to see the full narrative resolution.
Language Select Omission: Unlike many Sega-published titles of the era, Alien Soldier has no in-game language select despite its European release. The game’s text is minimal by design (Treasure leaned on visual storytelling), making the omission largely academic.
Phase 1 Hidden Frame Data: Several frames of Epsilon-Eagle’s transformation animation contain detail only visible when the game is paused on precise frames in an emulator with frame-advance. The animation cel work is noticeably more detailed than what’s visible at normal speed — a common Treasure production touch seen also in their GBA-era work.
Speedrun & Community Tricks
The Alien Soldier community (active primarily at SDA and later speedrun.com) has documented the following as part of competitive routing:
- Supereasy Any% is the primary accessible category; the extra continue trick is required routing in most runs
- Hardtype No Major Glitches bans the fire-cancel exploit and teleport invincibility abuse
- Stage-select-assisted practice runs are the universal recommendation for new players before attempting a full Hardtype clear
- The Seven Force phase skip is allowed in all major categories and is considered a tech skip rather than a glitch