First off I am not an accountant but (as usual) the downside is overstated to gee up the audience.
Yes there would be a VAT (Sales tax to those outside the EU) liability where goods or services were supplied - and that would need to be taken into account when setting values.
Ignoring VAT - yes the sum "invested" by participants would have to be entered into the accounts as income received but corporation tax would only be payable on any net profits for the business at the end of the company financial year. There is no tax on income - only profit.
