Game link: Samus Regrets
I narrate/ramble in the video some of my thought process and such, but things:
What went right
Got lucky and got a workable idea pretty quick
Made a list of everything that *had* to be in the game for it to work and focused on those things before anything else
Was therefore able to get all the essential game elements done in time
what went wrong
Never got round to the list of extra things that would have made the game better, except sound, which… well that probably didn’t help any, anyway
Wasted a lot of time creating a level editor/building levels and then going over them again when I had detail finished, which meant things had to get cut
Didn’t have time to make the ice beam work as it should have
Forgot to get time off work on Monday… so tired 😛
Things I had to cut 
Enemy types. There are quite a few varieties in the game, all with different behaviours, but it would have been nice to have had more. You can see in some areas of the game I clearly designed the level to incorporate specific classic metroid enemies (like the creatures in norfair that live in the walls and stretch their necks out… whatever they are) but just didn’t have time to get them done so ended up putting other enemies in their place
I wanted bosses. That was probably unrealistically ambitious, but I would have liked to, and I arranged a couple of rooms in the game in the hope that I would have had some extra time for this.
Lift animations. Right now they work more like teleporters, but it would have felt much better with the classic metroid elevator transitions.
So for next time, if I’m still using Blitzmax, I should try to develop a simple open source tile/level editor in advance or something to save a lot of time. I could probably use an already existing tile/level editor, but I really enjoy coding level editors for some reason 😛