I enjoyed playing. I'm glad I found this game from 16 years ago for me to play. I played through once on the easiest difficulty to learn the game, and another time on the hardest difficulty because I enjoy challenges. I have 5 criticisms:
1. The player power spikes a bit too hard. I played on terminator difficulty, and after I beat level 5, the game became much easier (I prioritized speed upgrades)
2. The game mentions bonus effects from suits and swords, and only gives details for dragon's eye suit. I'd prefer it if I was told what the effects of each of the suits and weapons are.
3. I dislike the lack of information in the weapon and suit shop as well as the abilities. You can only learn about the items after you've purchased them. I'd like it if the abilities let you know how much damage they'd do.
4. There's a bug where if you have some armor or weapon and you restart the game, your new game will give you normal stats, but it'll treat you as if you still have that armor or equipped. If you change your equipped armor or weapon, you'll lose stats. I managed to get negative hp on my character. (starting another new game fixes this issue though, so it's not that bad of a bug)
5. The player as well as the enemy don't always die when they drop to or below 0 hp. The player is able to consistently cheat death.
I enjoyed the upgrade system & the simplicity of the game. The terminator difficulty felt perfect for the first few levels. The later levels were easier, which is nice because it made me feel like I picked strong upgrades.