I want to like this because it feels quite polished in a lot of ways. It controls quite well, the music is cool, and there is a decent variety of stuff to build. The are mouseover tooltips, a minimap that can control the camera, and pathfinding that navigates randomized terrain.
I like exploring, and it's cool that this is combined with a base building game. However, I spend so much of my time exploring and finding nothing. The map is huge, and there isn't enough interesting stuff to fill it.
There's also a good chance that one of the necessary resources isn't anywhere near the base.
There's no danger to the explorer, and once I make a couple towers, there's no danger to the base until the gryphon is released. That means I can safely ignore my base for most of the game.
It's just not very exciting, and not very chaotic.
I suggest making the normal enemies have a chance of targeting the explorer, the towers, and the resource gatherers, so players have to consider defending them too. If a tower is occasionally destroyed at base, it gives the player more reason to check back and replace it. If the explorer is chased by monsters, the player can deploy a tower to fight. If the explorer is killed, a new one spawns at base.
Have the defenses be upgradable, but requiring a rare resource that can only be acquired once per location, so the player has more to look forward to when exploring.