Although its biggest inspiration is probably the Wizardry series of games — at least, that is what it most seems like to me — QuestLord, by LavaLevel, is an excellent homage to the dungeon crawlers and first-person tiled RPGs of yesteryear. If you played and loved series such as Might and Magic, Akalabeth, or Wizardry, you’ll feel right at home in QuestLord. However, the game also draws a bit of inspiration from Ultima Underworld as well, most notably in its innovative combat system. And best of all, it’s available for both iOS and Android, for the quite reasonable price of $1.99.
QuestLord offers a full-fledged magic system, turn-based combat, lots of quests, and a more or less entirely non-linear plot-line. You’re free to explore the world more or less as you please, limited only by how well your health holds up against the variety of monsters the game throws at you.
Oh, and it’s worth noting that the game might be fairly easy to mod; it stores its level data in flat text files, which can easily be viewed with any text editor. The exact scheme that veteran developer Eric Kinkead (check out his résumé!) uses to map the data in the text files to what you see on screen would take a bit of figuring out, but once that hurdle is accomplished, there’s no messy de-encoding/re-encoding step that will need to be performed.