Me, not having major complaints? Wow!
Phew, I finally beat it (On expert, of course). Took me a couple days. For just one level, I'd say... it's been a while since that last happened.
This game is awesome. Not a phrase you can hear from me often. It definitely catches that old school look and feel and manages to be quite difficult, but it is fair difficulty, no cheap tricks anywhere. You get hit or killed, next time you know it's there and hopefully know how to beat it. However, it needs a few tweaks before it's perfect. Because of that, I give it a 9/10, and I'll try to describe what's lacking. It's pretty much nit-picking. Because I don't have anything major to complain about.
Gameplay. Perfect. Just perfect. One little bit, more on topic of level design, actually: some of the moving platforms (Namely, the two on the right side of room 1_11) are not synchronized, causing long waits if you don't make it in time for the first time they get in position for you to make the jump. It might be intentional, for the retro feel, but still. Also, there's an area (Room 1_20, I think) where if you don't activate a moving platform right away, you will get hit by one of the ghost heads.
Graphics. The only thing that is a little bit off is Arkus' sprite. His left arm. I don't know, it just sticks too far out from his body - if his anatomy is anything near human, it'd get tired very quickly. Maybe it's just me, or perspective. Also, the scenery is a bit too bland-brownish, but that's likely intended.
Music. That's what I call videogame music! Very fitting, loops greatly and fits the action. There's a little moment at around 2:00-2:10 (Start the game, skip the exposition) where the piano gets louder that may be a bit distracting.
That's about it. Two things I should applaud: loquacious blue dragon space pirate. XP system and the way it's tied in to life.
Looking forward to the second episode. Keep up the good work!