Painless Smile Actually wasn't all that bad. By all means, it's not great. But in terms of something you could just stumble upon and play for about five minutes, and leave, it's good in that regard. However, the screen's a little too short, and that leads to some cheap shots. Sorta got hit like a bulldozer around wave 7 because of how fast the enemies were, and how small the screen is. The weapons felt similar, but fired slightly different enough to not warrant any complaints. I also had no idea what was going on, if there was a story, why this random guy was just shooting these weird humanoids, and why there's suddenly green bursts that teleport him to another place.
I encourage you to keep making stuff like this. I've played similar corridor shooters in flash. This reminds me of an angsty flash game from 2008, and I really like it for that. If you added more onto it, perhaps add some more depth to the gameplay, explaination, or just general quality of life improvements, like bobbing the model up and down very slightly or something like that, it'd make for a little better experience.
Good hustle, my man. Keep it up!