As simple as the puzzles are, the combat is simpler still. The emphasis is very much on hitting things with your sword, and you can upgrade the length, width and power of your blade, or give it special powers like being able to hit enemies through walls or shoot lasers, so as long as your health bar is full, your sword will be huge, and you'll breeze through dungeons with very little risk to yourself. You can also use your sword to pick up items, and when you're at full size, that's an incredibly useful ability.
Should you take even a single point of damage however, your enormous blade goes away, and you're back to the basic model. In theory, this is how the game is supposed to be played, but the difference is so great, it's hard not to feel underpowered, especially when you lose basic abilities like being able to swing your sword rather than just stab. There's plenty of variety though, as you can buy and find new swords, or get them from completing side quests, so if one sword isn't working it's a pretty simple matter to just switch to another. Not all the swords are entirely serious either and it's hard not to smile when you're whacking enemies with a huge fish.
There's a lot of fun to be had with 3D Dot Game Heroes, but it puts too much effort into recreating the Zelda games and not enough into doing much new. Nostalgia will only take you so far sadly, and 3D Dot Game Heroes doesn't have much else to offer. The gameplay and plot lack depth on purpose, because they're aping a game nearly a quarter of a century old, without realizing that that isn't anywhere near as charming in a new game as it is in a much-loved classic.
The Bottom Line: It's a funny and charming little game, but it plays the retro card a little bit too much. A lot of the gameplay feels very dated in a modern game, and you can't make the same allowances for age that you can with an actual retro title. There's plenty to do, but it's worth trying it before you make a more serious investment.
Recommendation: If you have fond memories of the original Zelda game, then there will be a lot in 3D Dot Game Heroes that will resonate with you, but if you're not a fan, you might find it lacking.