10,000,000 essentially takes the core gameplay concept of Chuzzle (dragging whole rows and columns to make a match) and adds classic RPG elements. It's easy to pick up, and it's not TOO hard to put down. If you like slow-paced contemplative tile-matching that make take you an hour to complete a run, this is gonna be a little much for you.
It is expected that each run will only last a short time (a minute or two in the early stages), because you are working against the clock. Your hero runs through a long dungeon (displayed at the top of the screen) and meets various obstacles. The type of obstacle will determine what type of match will allow you to advance. The hero runs fast enough to regain time, but the screen keeps scrolling slowly while you are working on an obstacle.
Doors and treasure chests require that you match Key tiles. Enemies can be attacked with Sword or Staff tiles. Most enemies will need to be attacked multiple times; they have health bars to let you know how you're doing. You must also endure enemies' attacks, which will reduce your timer (there is no HP, only the timer). Shield tiles can give you damage reduction, and Item tiles can generate useful consumable items for your inventory (one-use weapons and magic spells, keys, food to add time to the clock, etc).
You also match Wood and Stone tiles, which accumulate resources that are used back in your hub area in between dungeon runs. You build item shops which allow you to upgrade the effectiveness of each type of tile matches. You'll accumulate Gold and EXP with each dungeon run. Gold can be spent on your various tiered equpiment upgrades, and EXP can be spent on a variety of one-off permanent bonuses (like decreasing the cost of weapon upgrades, or granting bonus time for long combos).
You'll also be given up to three objectives to try to complete at the start of each run. These range from "match [X number] of Stone tiles over the course of your run" to "defeat an enemy by only using Items"
"Beating" the game requires getting a cumulative 10,000,000 points across all your runs, though you can keep playing after that.
I've played through the game before, and I'm on my second playthrough now that some new content has been added. It's a nice way to kill a few minutes before I go to work, or a few hours when I get home.