Introduction
Xanthiom is an Atari 2600 homebrew game developed by Mathan Games in 2023. The player controls Lieutenant Grisham, on a mission to rid the threats to the galaxy on the planet Planet Coati 5. This homebrew is very much a take on what the original NES Metroid would be like on the Atari 2600 with the limitations therein. I found this to be a pretty fun game and it's short enough that the lack of saving or continuing isn't that big of an issue.
This TAS uses version 5 of the game which as of 14 July 2023 is the latest version. The game is available from the developer here: https://mathangames.itch.io/xanthiom-2600
The goal of this TAS is to collect every upgrade in the game before beating the game. The game's page on itch.io has full game maps for the two areas of the game, although one of the rooms with an upgrade is missing in the first map for whatever reason. I forgot about that one when working on this and had to add inputs to grab it. Thankfully this game seems entirely sync safe including boss behavior.
Run notes
- Emulator used: BizHawk 2.9.1
- A2600Hawk core
- 100% item completion
- Takes damage to save time
Mechanics and techniques
Delaying the start for a frame
I delayed starting the game for a frame. All this does is allow the game to render the projectiles as squares rather than lines. This doesn't seem to actually affect shot hitboxes or affect sync but it does help with visibility for the viewers.
Upgrade list
Here's a quick rundown of the upgrades in the game.
- Missile tank
- This adds 5 maximum missiles to Grisham's arsenal. Missiles don't actually do extra damage over the beam shot but they always shoot straight. Missiles are normally only needed for exactly one door in the entire game so in a normal any% run they're kind of useless. However, the wave beam upgrade makes the beam sometimes miss an otherwise successful hit so missiles are incredibly useful on the second, more mobile boss.
EDIT 16 July 2023: The developer got in contact with me saying that the damage for missiles is bugged and a new version will give it the proper damage values. This is the main reason for cancelling this submission as it should also speed up the boss fights.
- Energy tank
- This adds 100 extra energy for survival. This is pretty straightforward although there's no knockback. Damage is by contact over time with harmful objects.
- Jump boots
- This increases the vertical jump height from 3 blocks to 4 blocks. This is required to navigate most of the map.
- Wave beam
- This upgrade adds a vertical wiggle to the beam shot. This would help with more coverage with the beam shot but sometimes it makes the beam move in a way that would cause it to miss in situations where a straight shot would hit. It's not a great upgrade though it has to be obtained for 100% completion.
- Varia suit
- This protects Grisham from passive damage while in the second map of the game.
- Power beam
- This doubles the damage of both the beam shot and the missiles. This is optional but speeds up the second boss fight.
Enemy HP
Enemy HP is found at address 3 4 bits. The beam shot and missiles deal the same amount of damage so missiles.
0x60 but offset by Jumping
Jumping will always try to go for the full height of the jump. This is a problem when there are potential objects above to get caught on. Jumping can also sometimes delay when the next shot can be fired so jumps sometimes have to be delayed due to that.
Bosses
The first boss, a big green boss, can be shot anywhere on the body. The only real thing to speed it up is to get close enough to keep up a high firing rate and to end the fight as close to the Varia suit upgrade it drops when it dies.
The second boss, a mobile purple boss, can be somewhat manipulated in its shot timing with certain actions. Due to the boss movement and the wave beam upgrade, a mix of beam shots and missiles are used to damage the boss.
Special thanks
- Mathan Games for making the homebrew game
- This video for showcasing a lot of neat homebrew games, which is how I learned of this game in particular
nymx: Claiming for judging.
Darkman425: Cancelling this submission due to the developer working on a newer version that fixes the missile damage. Also fixed a small error in the submission since I apparently can't do binary math.