I like the idea but there is a lot of toil in the game and the basic game loop seems meh. It's early access though so there is still time to improve.
Some examples: the basic game loop is to buy resources, bid for contracts, build the tanks and deliver them. You have to do all of this manually: decide where to buy the resources from (different places with different prices but also different amounts), decide what to bid (kind of fun but no indication of how committed you'll be, you have to remember it all) and build them which really has no complexity yet and doesn't offer any ways to make choices here really. Delivery is not automatic and you can (and I have) forgotten to ship tanks. The choices here are insanely blunt: you can pay much more for slightly faster delivery. If you get the above loop right, you simply never do this. So again, it's a pointless tick-box exercise.
This is all wrapped in a research, engineer and design loop that has great potential. But after the first few years, R&D is more-or-less inconsequential and it's all about managing your delivery pipeline.
Constructively I hope that the real game will have the ability to pay for decent automation of the processes above. A genuine choice of doing it ok but without toil or well but with toil could work. Or a cost-based optimisation process. None of that exists yet.
The core idea is fun, you too can be a Merchant of Death. But as it is, it's hard work and little fun.

This game is 10% of what it could be right now.

Here's what we have:
British tech tree (with the ability to reverse engineer french and german tanks) and ww1 era tanks.

Here's what we will (hopefully) get:
French, German, American, Russian, and maybe some minor nation tech trees. Interwar, ww2, cold war, and modern era tanks.

Not to mention that fact that the entire method of designing and selling tanks will probably need a massive overhaul to accomodate systems not in ww1 tanks, such as stabilizers, thermals, FCS, autoloaders, and potentially others.

In summary, this game needs a few more years to get to it's full potential. The main reason i'm giving this a positive review is because I really want this game to be finished. However, I would say to not buy this game for now, although my opinion might change when Interwar comes out.

This game lacks a lot of content for the 29.99 price point. Also when the games description says ww1 to modern and you cant get past ww1 due to lack of content change your description to fit the game. I understand it is in early access but from what it seems it has been that way for awhile.