I agree with AmyMor's assessment, but I think you misunderstand. There's no need for less-demanding levels. The difficulty itself is fine. In fact, making it easier would make it less engaging, in my opinion. It's the fact that you only have 3 lives and no continues that is frustrating. Once you learn a level, it becomes quite a bit easier and a lot more satisfying. But it takes quite a lot of tries on some levels to learn how to do it properly. For me at least, having to play through all the earlier levels again and again just to have another 3 tries at, say, Level 6 is really annoying and time consuming. I have a job and a family; I don't have time to grind through 5 levels all day just to have a couple of shots at the one level I'm trying to practice. In the end, I just grabbed a trained version off CSDb so I could practice it with infinite lives (I did pay for the official version too, though, just fyi). This made it soooo much more enjoyable. It's a great game and I love it, and once I'm good at all the levels, I'm hoping to run through it on a single life, or at least on a single credit.
I know I could boot up Vice and use save states too, but it's so much more fun on a breadbin and CRT!
Also, I know this is a classic arcade style game, and maybe that's why you only give the player 3 lives and no continues. But in the arcade, the whole point of being stingy with lives was to make the player drop coins into the machine, not to make it impossible to get good at the game in a reasonable timeframe. And remember that some of the best arcade conversions for home systems gave you a bunch of credits to have fun with. I know, though, that a lot of home console games in the 80s were pretty difficult and stingy with lives too. But it's 2022 now, dude. At the very least, I would suggest providing a feature to allow the player to practice any level of choice in isolation. But then again, if you're a tragic C64 fanboi, you know where to find trainers, pokes, and the like anyway...
Like I said, I love the game, and I'm definitely going to be playing this for while. Great graphics, music, controls, and gameplay. If I had to gripe (apart from the time-consuming lives thing), I would say this. (a) Your robot feels like a snail. Does he have lead boots or something? (b) Some of the hazards are too hard to see at first. Once you've learned a level, you know where they are, so it doesn't matter so much. But initially, it's extremely frustrating to die because you brushed past a spike that's barely visible or blended into the background, or fall through a platform that you can't stand on (despite it initially looking like you can stand on it). These are cheap deaths, and it's very easy to lose all your lives in short order because of this and have to return all the way back to the start of the world, making it take longer and longer to learn the level that's giving you problems. Arrrrrrgh. But this complaint would be pretty much erased if you provided a level practice feature. (c) This is hands down the most annoying thing for me: Why the heck do you die just because you bump into the ceiling? Arrrrrrrrrrrrrrrrrrrrrrrrrrgh, so dumb. I hate it when games do cheap stuff like that.
But to end on a positive note: It's awesome, thanks for making this.