Welp, I'm officially in love with Rain-Slick 4. Everything's gorgeous, from the dungeons to the music to the insane variety of monsters. The dialog, flavor text, and plot are HILARIOUS and do a great job of lampooning RPG stereotypes and using the Penny Arcade characters. I've seen tons of nods to Zeboyd's other games and various other RPGs. For instance, one of the starting monsters (who's quite a strong magic user) is an elaborate Persona reference, with a name and appearance nodding to Philemon and skills like "Eternal Punishment" and "Revelation." I'm about 10 hours in and I'm 90% sure I'm near the end - the final boss has revealed itself and I'm doing sidequests.
Look, this is an extremely awesome RPG, it recaps the prior games in its opening cut scene, and it costs $5. It was also basically made by two guys. You could do a lot worse.